Co-channel interference is a serious technical issue in a heterogeneous 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) network, which may consist of many different types of service coverage such as macro cells, pico cells, and femto cells. Since all of these cells may use a single carrier, i.e. full frequency reuse, to communicate with User Equipment devices (UEs) served by the cells, the co-channel interference level in such a network could be considerably high and may become a bottle neck for sustaining cell throughputs at a certain level to meet required performance expectation, particularly for UEs on cell borders. This negative effect may significantly lower spectrum efficiency of a heterogeneous network.
As an advanced technical solution, Downlink (DL) Coordinated Multi-Point (CoMP) can play a role in combating co-channel interference by coordinating multi-cell operations in a cell cluster that provides a significant gain to bring back UE throughputs to meet required performance or even to reach a higher level. To achieve this goal, however, a specifically designed Media Access Controller (MAC) layer downlink scheduler is needed.
The existing situation is that DL CoMP technology is still in the phase of internal standardization and lab prototyping. Currently, DL CoMP related standardization is on its way and, as such, DL CoMP will soon be widely adopted and deployed in various heterogeneous networks worldwide. Thus, it is important, necessary, and valuable to a commercial enhanced or evolved Node B (eNB) product to be equipped with a smart downlink scheduler which is able to effectively and efficiently work with DL CoMP technology in a realistic heterogeneous networking environment.